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Augmentation Technique for Anterior Cruciate Ligament Injury
A u g m e n t a t i o n Tec h n i q u e f o r Anterior Cruciate Ligament Injury Hiromi Kazusa, MD, Atsuo Nakamae, Mitsuo Ochi, MD, PhD*
MD, PhD,
KEYWORDS Anterior cruciate ligament (ACL) Augmentation technique Partial rupture Remnant-preserving technique Double bundle KEY POINTS The anterior cruciate ligament (ACL) augmentation technique has potential advantages in terms of proprioceptive function of the knee, revascularization of the graft, and contribution to knee stability. The decision of whether the remaining bundle represents partial rupture or complete rupture of the ACL was made on the basis of physical, magnetic resonance imaging, and arthroscopic findings in a comprehensive manner. Single-bundle ACL reconstruction with remnant-preserving technique is performed in cases of partial rupture of the anteromedial (AM) or posterolateral (PL) bundle of the ACL, and double-bundle ACL reconstruction with remnant-preserving technique is done mainly for patients with continuity of the ACL remnant between the tibia and either the femur or posterior cruciate ligament after complete rupture of the ACL. The femoral and tibial bone tunnel opening should not be placed at the center of the anatomic attachment of the bundle when using hamstring tendons, because the graft shifts to the anterodistal side in the femoral tunnel opening and to the PL side in the tibial tunnel opening. In cases of partial rupture of the AM or PL bundle of the ACL, surgeons should keep in mind that the remaining bundle is not completely intact and it is likely that the biomechanical function of the remaining bundle declines to some extent.
Anterior cruciate ligament (ACL) reconstruction has become a common treatment in orthopedic sports medicine. The normal ACL consists of 2 major functional bundles: the anteromedial (AM) bundle and the posterolateral (PL) bundle. Traditional singlebundle ACL reconstruction has concentrated mainly on the functional restoration of the AM bundle. Recently, several studies have shown that the central anatomic single-bundle ACL reconstruction can restore normal knee function.1–3 With this method, the tibial and Conflict of interest: The authors report no conflict of interest. Department of Orthopaedic Surgery, Integrated Health Sciences, Institute of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan * Corresponding author. E-mail address: [email protected] Clin Sports Med 32 (2013) 127–140 http://dx.doi.org/10.1016/j.csm.2012.08.012 sportsmed.theclinics.com 0278-5919/13/$ – see front matter Ó 2013 Elsevier Inc. All rights reserved.
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femoral tunnels are well placed in the center of their respective ACL footprints. Moreover, interest in double-bundle ACL reconstruction has been growing because of its greater potential to restore knee kinematics.4–8 Double-bundle ACL reconstruction can mimic more closely the normal structure of the ACL. Restoration of the biomechanical function is essential in ACL reconstruction. However, biological healing of the graft is vital to the achievement of satisfying clinical results. Accelerated biological healing is necessary not only for early return to sports but also for reliable remodeling of the grafted tendon. ACL AUGMENTATION Potential Advantages
Arthroscopic examination for ACL reconstruction occasionally demonstrates a relatively thick and abundant ACL remnant. In standard single-bundle or double-bundle ACL reconstruction, the ACL remnant is totally debrided to enable clear visualization of the femoral and tibial bone tunnels. However, recent studies have shown that human ACL remnants contain several types of mechanoreceptors. These mechanoreceptors may provide positive effects on the proprioceptive function of the knee.9–12 In addition, some studies have shown that the ACL remnants provide some biomechanical stability to the knee.13,14 Therefore, ACL reconstruction that preserves the remnant by using the ACL augmentation technique might have several advantages: 1. The ACL remnant may contribute to knee stability and guarantee mechanical strength in the early postoperative period. 2. With respect to the proprioceptive function of the knee, nerve fibers may originate from the preserved ACL remnant and regenerate mechanoreceptors around the augmented graft. 3. The ACL remnant may accelerate cellular proliferation and revascularization of the grafted tendon. Indications
The ACL remnant often maintains a bridge between the tibia and either the intercondylar notch or posterior cruciate ligament (PCL). Even when the substantial remnant maintains a bridge between the tibia and the intercondylar notch, the femoral attachment of the ACL remnant is often positioned abnormally. These cases represent a complete rupture of the ACL. However, sometimes a partial rupture of the AM or PL bundle of the ACL can be observed. In the authors’ previous studies, the frequency of partial rupture was 10% during 2002 and 2005,15 and 20% during 2006 and 2008.13 In these cases, although rupture of the AM bundle or PL bundle could be seen, the other bundle was well preserved, with an attachment of anatomic femoral origin. Partial rupture of the AM or PL bundle of the ACL
Previously, the authors performed the ACL augmentation procedure only for cases of partial rupture of the ACL. In these cases, single-bundle reconstruction of the ruptured bundle is desirable to minimize damage to the femoral attachment of the remaining bundle. Therefore, isolated AM bundle or PL bundle rupture is an indication for the single-bundle augmentation technique. Continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL
In 2008, the authors began performing the ACL augmentation procedure even for patients with continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL. In this complete rupture group, the
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indication for the procedure comprises cases whose ACL remnant maintains a ligamentous bridge between the tibia and either the intercondylar notch or PCL. Initially, central single-bundle ACL reconstruction with the remnant-preserving technique was performed for patients with a complete rupture. Recently, double-bundle reconstruction with the remnant-preserving technique has been performed to mimic more closely the normal structure of the ACL. Preoperative and Intraoperative Evaluation
It is sometimes difficult to decide whether the remaining bundle represents a partial or complete rupture of the ACL. The decision was made after thorough consideration of physical, magnetic resonance imaging (MRI), and arthroscopic findings.13 Quantitative evaluation of anteroposterior knee laxity can be one indicator for this decision. Partial rupture of the ACL was suspected when the side-to-side difference in the anterior displacement of the tibia was less than about 5 mm and a delayed firm end point was noted. The anterior displacement of the tibia was measured by the KT-2000 knee arthrometer or Kneelax-3 at 30 lb (13.6 kg). MRI also provides important information for evaluation of the femoral attachment of the bundles. However, the final decision was made after arthroscopic confirmation of the status of the injured ACL. Evaluation by Arthroscopy
Arthroscopic intra-articular inspection was performed through the standard AM portal, anterolateral portal, and the far AM portal. A thorough arthroscopic probing is needed to precisely assess the ACL remnant patterns. Careful probing on the femoral side is important because most ACL ruptures occur in the proximal half. Partial rupture of the ACL was suspected when ligamentous continuous fibers were observed between the tibia and the anatomic femoral insertion of the ACL. Furthermore, arthroscopic examination should be performed in a figure-of-4 position and at various knee-flexion angles to consider the different tension patterns of the 2 bundles.16–19 Classification of the ACL Remnant
The ACL remnant pattern was thoroughly examined to determine the treatment strategy, and was classified (Box 1). Groups 1a and 1b indicate single-bundle reconstruction with the remnant-preserving technique. Groups 1c, 2a, 2b, and 2c indicate double-bundle reconstruction with the remnant-preserving technique. It is important for surgeons to keep in mind that, even in the partial rupture cases, the remaining bundle is invariably not completely intact. It is likely that the biomechanical function of the remaining bundle declines to some extent. SURGICAL TECHNIQUE
Since 1992, the senior author has performed the ACL augmentation technique when indicated.20 However, the early procedures required 2 incisions at the medial aspect of the proximal tibia and at the lateral femoral condyle, because the grafted tendon was fixed to the femur through the over-the-top route. This early technique had a serious flaw, because it was not a true reconstruction that restored normal ACL anatomy. Therefore, Ochi started to perform the 1-incision technique for ACL augmentation in 1996. Compared with the 2-incision technique, the 1-incision technique is less invasive and enabled reconstruction of the ACL in the anatomic portion. Here the authors introduce the ACL augmentation technique for partial and complete rupture of the ACL.15,21–23
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Box 1 Classification of the ACL remnant Group 1: Partial rupture of the ACL Group 1a: Partial rupture of the PL bundle The ligamentous AM bundle of the ACL had an attachment of femoral origin and was well preserved. Group 1b: Partial rupture of the AM bundle The ligamentous PL bundle of the ACL had an attachment of femoral origin and was well preserved. Group 1c: Partial rupture of the ACL but the remaining bundle could not be ascribed to either the AM or PL bundles Group 2: Complete rupture of the ACL Group 2a: ACL remnant bridging the PCL and tibia The normal attachment of the ACL to the intercondylar notch was entirely lost. Group 2b: ACL remnant bridging the roof of the intercondylar notch and tibia There were no ligamentous continuous fibers in the normal attachment of the ACL to the femur. Diameter of the remnant was somewhat attenuated. Group 2c: ACL remnant bridging lateral wall of the intercondylar notch and tibia Attenuated ACL remnant healed to the lateral wall more arthroscopically anterior than its anatomic origin. There were no ligamentous continuous fibers in the normal attachment of the ACL to the femur. Group 2d: No substantial ACL remnants bridging the tibia and either the femur or the PCL
Patient Positioning and Graft Harvest
The patient was placed supine on the operating table, and a tourniquet was applied around the upper thigh. The knee was placed at 90 of flexion with a foot support and lateral thigh support, and full range of motion was possible. A longitudinal skin incision of approximately 4 cm was made on the anteromedial aspect of the proximal tibia. Semitendinosus and gracilis tendons were identified, and only the semitendinosus tendon was harvested using an open tendon stripper. For the preparation of a tibial bone tunnel, the periosteum was divided longitudinally and reflected medially, just medial to the tibial tubercle. Graft Preparation
In the cases of single-bundle reconstruction with the remnant-preserving technique, a quadrupled semitendinosus tendon was used as the graft for the augmentation. An appropriate size of the EndoButton CL (Acufex; Smith & Nephew, Mansfield, MA) was determined according to the length of the femoral bone tunnel. The quadrupled semitendinosus tendon was connected to the EndoButton CL at the femoral side and to the polyester tapes (EndoButton tape; Acufex; Smith & Nephew) at the tibial side. In the cases of double-bundle augmentation, 2 pieces of doubled semitendinosus tendon were used as a graft. The semitendinosus tendon was divided in half. Each tendon was then doubled, and EndoButton tapes were mechanically connected in series to each free end of the graft. The EndoButton CLs were then connected to each loop end.
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Portal Placement
A 3-portal technique was used. The anterolateral portal was placed as medial (close to the lateral edge of the patellar tendon) as possible to allow visualization of the entire lateral wall of the notch. The AM portal was placed above the joint line, adjacent to the medial edge of the patellar tendon. Finally, the far AM portal was placed as inferior (close to the anterior portion of the medial meniscus) as possible, and 2.5 to 3 cm medial to the medial border of the patellar tendon. The use of this far AM portal for instrumentation allows the AM portal to be used to view the lateral wall of the intercondylar notch. Femoral Bone Tunnel Preparation
There are 2 major techniques for creating a femoral tunnel. One is drilling through the tibial tunnel (transtibial technique) and the other is drilling through the far AM portal (far AM portal technique). The authors regularly use the far AM portal technique, because this technique allows more flexibility in accurate anatomic positioning for femoral tunnel drilling than the transtibial technique. It has been confirmed that the far AM portal technique is as effective as the transtibial technique and results in good restoration of joint stability and knee scores, despite a shorter femoral tunnel length and an inferoposterior position of the EndoButton.24 Excision of the femoral stump using a motorized shaver system was kept to a minimum. No notchplasty was performed. The targeted point for the femoral tunnel was marked with a microfracture awl with the knee at 90 . When performing singlebundle or double-bundle ACL reconstruction using hamstring tendons, the authors hold that the femoral and tibial bone tunnel opening should not be placed at the center of the anatomic attachment of the bundle. The graft is pulled and shifts to the anterodistal side of the femoral tunnel opening and to the PL side of the tibial tunnel opening. When the femoral tunnel is created at the center of the bundle’s femoral footprint, the point of application of force at the tunnel opening shifts from the center of the femoral footprint to an anterodistal direction. The same can be said for the tibial tunnel. Thus, one must recognize that the center of the ACL’s footprint is different from the optimal center of the bone tunnel. The center of the tunnel opening is not the central point of the application of force. It may be true that the biomechanical main part of the femoral attachment of the ACL is on the resident’s ridge, and the remaining part is attached to the posterior portion of the ridge. However, although the femoral tunnel opening can partially include the resident’s ridge, the authors maintain that the center of the femoral tunnel opening should be placed behind the resident’s ridge, for reasons discussed previously (Figs. 1 and 2). Single-bundle reconstruction with the remnant-preserving technique (Groups 1a and 1b)
In cases of PL bundle rupture (group 1a), the aim was to position the central portion of the femoral tunnel between 2 o’clock and 2:30 (left knee) or between 9:30 and 10 o’clock (right knee).23 The marked position indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the AM bundle (see Fig. 1A). Once again, surgeons should keep in mind that the remaining bundle is not intact and that the biomechanical function of the remaining bundle probably declines to some extent. It is unsuitable to create a bone tunnel at the center of the PL bundle attachment. A passing pin was inserted using the far AM portal technique to create a femoral tunnel with 110 to 120 of knee flexion. The length of the tunnel was calculated after increasing the diameter to 4.5 mm with the EndoButton drill. Then a femoral bone socket was created using a headed cannulated reamer of the same diameter as that of the proximal portion of the graft.
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Fig. 1. Femoral bone tunnel placement (short arrow) in single-bundle ACL reconstruction with remnant-preserving technique. (A) In cases of posterolateral (PL) bundle rupture (group 1a), the center of the femoral tunnel was aimed at clock positions between 2:00 and 2:30 (left knee) or between 9:30 and 10:00 (right knee). The marked position (short arrow) indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the anteromedial (AM) bundle. (B) In cases of AM bundle rupture (group 1b), the aim is to position the center of the femoral tunnel between 1:30 and 2:00 (left knee) or between 10:00 and 10:30 (right knee). The marked position (short arrow) indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the PL bundle.
In cases of AM bundle rupture (group 1b), the aim was to position the center of the femoral tunnel between 1:30 and 2 o’clock (left knee) or between 10 o’clock and 10:30 (right knee).23 The marked position indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the PL bundle (see Fig. 1B). Double-bundle reconstruction with remnant-preserving technique (Groups 1c, 2a, 2b, and 2c)
Through the far AM portal, a passing pin was directed at the targeted point, and the femoral tunnel was subsequently drilled through this portal. Furthermore, the centers of the femoral tunnel openings should be placed posterior to resident’s ridge (see Fig. 2).22 In group 2b, both the targeted points for the AM and PL femoral tunnels are posterior to the femoral attachment of the ACL remnant. In groups 1c and 2c, although the targeted point for the PL femoral tunnel is distal and posterior to the femoral attachment of the ACL remnant, the targeted point for the AM femoral tunnel is proximal and anterior to the ACL remnant, because the positions of the ACL remnants in groups 1c and 2c are more posterior than those in groups 2a and 2b. Therefore, in groups 1c and 2c, the ACL remnant is sandwiched between the 2 grafted tendons. The passing pin was drilled through the femur to emerge on the lateral aspect of the thigh. After the passing pin was drilled, the procedure was the same as for singlebundle augmentation (see Fig. 2C). Tibial Bone Tunnel Preparation
Tibial attachment of the ACL remnant is a useful landmark for orientation because in most cases the tibial side of the ACL remnant is almost normal. A longitudinal slit was made at the center of the ACL remnant through the AM portal (Fig. 3A). The tip of the tibial drill guide (Director Drill Guide System; Acufex; Smith & Nephew) was inserted
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Fig. 2. Femoral bone tunnel preparation in group 2b (ACL remnant [black arrow] bridging the roof of the intercondylar notch and tibia; right knee). (A) The targeted point for the PL femoral tunnel was marked with a microfracture awl with the knee at 90 . (B) The point for the AM femoral tunnel. (C) Femoral bone tunnels for double-bundle augmentation. (D) Schematic (left knee) of femoral tunnel placement for AM and PL bundle.
through the AM portal. The tip was then put through the slit of the ACL remnant at an angle of up to 65 to the tibial plateau to allow visualization of the tip of the Kirschner wire (Fig. 3B).22 Single-bundle reconstruction with remnant-preserving technique (Groups 1a and 1b)
In cases of PL bundle rupture (group 1a), the tip of the drill guide was positioned in the center of the tibial insertion of the whole ACL. Then a 2.0-mm Kirschner wire was inserted using the drill guide. When the position of the Kirschner wire was satisfactory, the wire was carefully advanced by a conventional cannulated reamer to create a tibial bone tunnel. The size of the reamer was 0.5 mm smaller than the diameter of the distal portion of the graft. The tibial tunnel was then enlarged to the graft diameter with the appropriate tunnel dilator. In cases of AM bundle rupture (group 1b), the tibial tunnel opening should be positioned as anterior as possible within the tibial footprint of the ACL.23 The position of the guide wire was then checked with the knee extended, to see if the guide wire impinged on the roof of the intercondylar notch. Double-bundle reconstruction with remnant-preserving technique (Groups 1c, 2a, 2b, and 2c)
The tip of the tibial drill guide was put through the slit of the ACL remnant. Two 2.0-mm Kirschner wires were inserted into the tibial attachment of the ACL remnant using the
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Fig. 3. Tibial bone tunnel preparation in group 2c (ACL remnant [long black arrow] bridging lateral wall of the intercondylar notch and tibia; right knee). (A) A longitudinal slit was made at the center of the ACL remnant. (B) The tip of the tibial drill guide was put through the slit of the ACL remnant. (C) The Kirschner wire for the PL bundle (short black arrow) was inserted at 8 mm posterior to the wire for the AM bundle (short white arrow).
drill guide. The drill guide was set at an angle of up to 65 to the tibial plateau, to allow visualization of the tip of the wires. The Kirschner wire for the AM bundle should be inserted to enable the tibial tunnel opening of the AM bundle to be positioned as anterior as possible within the tibial footprint of the ACL.22 The Kirschner wire for the PL bundle was inserted at 8 mm posterior to the wire for the AM bundle to keep 2 to 3 mm thick of bony wall between the tibial bone tunnels (Fig. 3C). Therefore, it is necessary to make a longitudinal slit in the ACL remnant to visualize the tips of the guide wires. In addition, when using the transtibial technique, it is difficult to find the tip of the Kirschner wire for the PL bundle in the slit, because this technique requires the wire to be inserted at a shallower angle to the tibial plateau. As a result, the wire for the PL bundle will be parallel to the preserved ACL remnant. Therefore, the use of an image intensifier is required for intraoperative localization of the wire when using the transtibial technique. However, the use of an image intensifier has several risks including radiation exposure, extended time in surgery, infection, and lower accuracy of measuring the distance between the wires than arthroscopy. The authors recommend the far AM portal technique, because it does not impose any restrictions on the angle of the tibial tunnel. Increasing the inclination of the tibial tunnels to 65 allows for better visualization of the tips of the guide wires. After the passing pin was drilled, the procedure was the same as for single-bundle augmentation.
ACL Augmentation Technique
Graft Passage and Fixation
Graft passage depends on the patterns of the ACL remnant and can be either through or above the slit of the ACL remnant.22 Graft passing through the slit of the ACL remnant
For cases such as partial rupture of the PL bundle, if the graft passes above the ACL remnant, the positional relationship is anatomically incorrect and there is a danger of impingement, whereby the graft should pass through the slit of the ACL remnant. To prepare for this method, a curved hemostat was passed through the slit to create a passage to the intra-articular aperture of the femoral tunnel. All of the grafts for the PL bundle as well as grafts for the AM bundle in groups 2a and 2b are indications of this method. Fig. 4 shows an example of a graft passage for the PL bundle in group 2c. The creation of a passage through the ACL remnant allows minimal impingement of the ACL remnant against the reconstruction graft and the roof of the intercondylar notch. Graft passing above the ACL remnant
As for the grafts for the AM bundle in groups 1b, 1c, and 2c, a looped Ethibond suture passed above the ACL remnant (Fig. 5). The graft composites were introduced from the tibial tunnel to the femoral tunnel using the looped Ethibond suture (Fig. 6). The
Fig. 4. Preparation of graft passage for the PL bundle in group 2c (right knee). (A) A curved hemostat was passed through the slit (arrow) to create a passage to the intra-articular aperture of the femoral tunnel. (B, C) A looped Ethibond suture for later introduction of the graft for the PL bundle was retrieved by the curved hemostat through the longitudinal slit in the ACL remnant. (D) An arthroscopic grasper was subsequently used to pass the retrieved Ethibond suture for the PL bundle into the created tibial tunnel for the PL bundle.
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Fig. 5. Preparation of graft passage for the AM bundle in group 2c (right knee). A looped Ethibond suture for later introduction of the graft for the AM bundle was passed above the ACL remnant and was retrieved into the created tibial tunnel for the AM bundle by an arthroscopic grasper.
Fig. 6. Graft passage of the PL and AM bundles in group 2c (right knee). (A) Both looped Ethibond sutures for introduction of the PL bundle graft (white arrow) and AM bundle grafts (black arrow) passed under and above the ACL remnant, respectively. (B) First, the graft for the PL bundle (arrow) was introduced from the tibial tunnel to the femoral tunnel. (C) Second, the graft for the AM bundle (arrow) was introduced into the joint. In groups 2c and 1c, the ACL remnant was sandwiched between the 2 grafted tendons.
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proximal side of the graft was fixed to the lateral femoral cortex by flipping the Endobutton and pulling the graft distally. Change in the length of the graft was examined during knee flexion-extension motion. In single-bundle augmentation, a tension force of 50 N was applied to the distal Endobutton tape connected to the graft and this was secured with 2 staples (Meira, Nagoya, Japan) at 30 of knee flexion. In double-bundle augmentation, a tension force of 30 N was applied to the EndoButton tape of each graft. The EndoButton tapes were fixed with 2 staples each at a knee flexion angle of 15 for the PL bundle and 40 for the AM bundle. Finally, the separated ACL remnant at the slit was sutured onto the graft to create a closed tube (Fig. 7). The authors first performed the ACL augmentation technique in 2011, using a quadriceps tendon– patellar bone autograft. Bone–patellar tendon–bone and quadriceps tendon can be good options for the augmentation technique (Fig. 8). CLINICAL RESULTS IN THE LITERATURE
In 2000, Adachi and colleagues20 reported that the joint stability and proprioceptive function in 40 patients who underwent the ACL augmentation procedure were superior to those of 40 patients who underwent standard ACL reconstruction during the same period. However, as mentioned, the early procedures needed 2 incisions and were not true reconstructions that restored normal ACL anatomy. Therefore, Ochi and colleagues15 started to perform the ACL augmentation 1-incision technique for the partial rupture of the AM or PL bundle of the ACL, publishing their first report in 2006. Later, Ochi and colleagues21 also showed that ACL augmentation using the 1-incision technique substantially improved joint stability, the joint position sense, and the Lysholm score postoperatively in cases of partial ACL rupture. Recently, other orthopedic surgeons also demonstrated favorable clinical results using the ACL augmentation technique.16,25–29 The preliminary results from Siebold and Fu16 using autologous doubled or tripled semitendinosus tendon showed good clinical outcomes for AM and PL bundle augmentation at an average of 1 year postoperatively. Ahn and colleagues28 reported good clinical and MRI results for
Fig. 7. Final arthroscopic view of double-bundle reconstruction with remnant-preserving technique in group 2b (right knee). In this group, both grafts for the AM bundle (hidden) and PL bundle (arrow) passed under the ACL remnant. The separated ACL remnant at the slit was sutured onto the graft.
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Fig. 8. ACL augmentation technique using quadriceps tendon–patellar bone autograft. (A) Quadriceps tendon–patellar bone autograft (black arrow, quadriceps tendon; white arrow, patellar bone). (B) Three-dimensional computed tomography image of the femoral side (arrow, bone block in the femoral tunnel). (C) Coronal computed tomography image of the femoral side (arrow, bone block in the femoral tunnel).
single-bundle ACL reconstruction using the remnant preservation and femoral tensioning technique. Longer follow-up is necessary before a definitive conclusion can be reached, especially regarding the double-bundle augmentation technique. Nevertheless, the authors believe that this technique of preserving the remnant tissue of the ACL is a valuable procedure, especially in terms of biological healing of the grafted tendon. In the near future, a navigation system may play an important role in the ACL augmentation procedure. SUMMARY
In ACL reconstruction, biological healing of the graft is vital to the achievement of satisfactory clinical results. The ACL augmentation technique has potential advantages in terms of proprioceptive function of the knee, revascularization of the graft, and contribution to knee stability. The decision of whether the remaining bundle represents partial or complete rupture of the ACL has to be made on the basis of thorough and comprehensive physical examination, MRI, and arthroscopic findings. Singlebundle reconstruction with the remnant-preserving technique is performed in cases of partial rupture of either AM or PL bundle, and double-bundle reconstruction with the remnant-preserving technique is performed mainly for patients with continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL. However, in cases of partial rupture of the AM or PL bundle, surgeons should keep in mind that the remaining bundle is not completely intact and that the
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biomechanical function of the remaining bundle probably declines to some extent. Although longer follow-up is necessary before a definitive conclusion can be reached, the authors believe that this technique is a valuable procedure. REFERENCES
1. Ho JY, Gardiner A, Shah V, et al. Equal kinematics between central anatomic single-bundle and double-bundle anterior cruciate ligament reconstructions. Arthroscopy 2009;25:464–72. 2. Asagumo H, Kimura M, Kobayashi Y, et al. Anatomic reconstruction of the anterior cruciate ligament using double-bundle hamstring tendons: surgical techniques, clinical outcomes, and complications. Arthroscopy 2007;23:602–9. 3. Kanaya A, Ochi M, Deie M, et al. Intraoperative evaluation of anteroposterior and rotational stabilities in anterior cruciate ligament reconstruction: lower femoral tunnel placed single-bundle versus double-bundle reconstruction. Knee Surg Sports Traumatol Arthrosc 2009;17:907–13. 4. Kondo E, Merican AM, Yasuda K, et al. Biomechanical comparisons of knee stability after anterior cruciate ligament reconstruction between 2 clinically available transtibial procedures: anatomic double bundle versus single bundle. Am J Sports Med 2010;38:1349–58. 5. Petersen W, Tretow H, Weimann A, et al. Biomechanical evaluation of 2 techniques for double-bundle anterior cruciate ligament reconstruction. Am J Sports Med 2007;35:228–34. 6. Hussein M, van Eck CF, Cretnik A, et al. Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up. Am J Sports Med 2011;40:512–20. 7. Buoncristiani AM, Tjoumakaris FP, Starman JS, et al. Anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy 2006;22:1000–6. 8. Fu FH, Shen W, Starman JS, et al. Primary anatomic double-bundle anterior cruciate ligament reconstruction: a preliminary 2-year prospective study. Am J Sports Med 2008;36:1263–74. 9. Adachi N, Ochi M, Uchino Y, et al. Contribution of mechanoreceptors in the anterior cruciate ligament to the joint position sense knee. Acta Orthop Scand 2002;73:330–4. 10. Denti M, Monteleone M, Berardi A, et al. Anterior cruciate ligament mechanoreceptors. Histologic studies on lesions and reconstruction. Clin Orthop Relat Res 1994;308:29–32. 11. Ochi M, Iwasa J, Uchino Y, et al. The regeneration of sensory neurones in the reconstruction of the anterior cruciate ligament. J Bone Joint Surg Br 1999;81:902–6. 12. Ochi M, Iwasa J, Uchino Y, et al. Induction of somatosensory evoked potentials by mechanical stimulation in reconstructed human anterior cruciate ligaments. J Bone Joint Surg Br 2002;84:761–6. 13. Nakamae A, Ochi M, Deie M, et al. Biomechanical function of anterior cruciate ligament remnants: how long do they contribute to knee stability after injury in patients with complete tears? Arthroscopy 2010;26:1577–85. 14. Crain EH, Fithian DC, Paxton EW, et al. Variation in anterior cruciate ligament scar pattern: does the scar pattern affect anterior laxity in anterior cruciate ligamentdeficient knees? Arthroscopy 2005;21:19–24. 15. Ochi M, Adachi N, Deie M, et al. Anterior cruciate ligament augmentation procedure with a 1-incision technique: anteromedial bundle or posterolateral bundle reconstruction. Arthroscopy 2006;22:463.e1–5.
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16. Siebold R, Fu FH. Assessment and augmentation of symptomatic anteromedial or posterolateral bundle tears of the anterior cruciate ligament. Arthroscopy 2008; 24:1289–98. 17. Petersen W, Zantop T. Partial rupture of the anterior cruciate ligament. Arthroscopy 2006;22:1143–5. 18. Sonnery-Cottet B, Chambat P. Arthroscopic identification of the anterior cruciate ligament posterolateral bundle: the figure-of-four position. Arthroscopy 2007;23: 1128.e1–3. 19. Sonnery-Cottet B, Barth J, Graveleau N, et al. Arthroscopic identification of isolated tear of the posterolateral bundle of the anterior cruciate ligament. Arthroscopy 2009;25:728–32. 20. Adachi N, Ochi M, Uchio Y, et al. Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients. Arch Orthop Trauma Surg 2000;120:128–33. 21. Ochi M, Adachi N, Uchio Y, et al. A minimum 2-year follow-up after selective anteromedial or posterolateral bundle anterior cruciate ligament reconstruction. Arthroscopy 2009;25:117–22. 22. Ochi M, Abouheif MM, Kongcharoensombat W, et al. Double bundle arthroscopic anterior cruciate ligament reconstruction with remnant preserving technique using a hamstring autograft. Sports Med Arthrosc Rehabil Ther Technol 2011;3:30. 23. Nakamae A, Deie M, Adachi N, et al. Augmentation procedure for partial rupture of the anterior cruciate ligament. Tech Knee Surg 2010;9:194–200. 24. Nakamae A, Ochi M, Adachi N, et al. Clinical comparisons between the transtibial technique and the far anteromedial portal technique for posterolateral femoral tunnel drilling in anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy 2012;28:658–66. 25. Kim SJ, Jo SB, Kim TW, et al. A modified arthroscopic anterior cruciate ligament double-bundle reconstruction technique with autogenous quadriceps tendon graft: remnant-preserving technique. Arch Orthop Trauma Surg 2009;129:403–7. 26. Yoon KH, Bae DK, Cho SM, et al. Standard anterior cruciate ligament reconstruction versus isolated single-bundle augmentation with hamstring autograft. Arthroscopy 2009;25:1265–74. 27. Sonnery-Cottet B, Lavoie F, Ogassawara R, et al. Selective anteromedial bundle reconstruction in partial ACL tears: a series of 36 patients with mean 24 months follow-up. Knee Surg Sports Traumatol Arthrosc 2010;18:47–51. 28. Ahn JH, Wang JH, Lee YS, et al. Anterior cruciate ligament reconstruction using remnant preservation and a femoral tensioning technique: clinical and magnetic resonance imaging results. Arthroscopy 2011;27:1079–89. 29. Lee BI, Kwon SW, Kim JB, et al. Comparison of clinical results according to amount of preserved remnant in arthroscopic anterior cruciate ligament reconstruction using quadrupled hamstring graft. Arthroscopy 2008;24:560–8.
MD, PhD,
KEYWORDS Anterior cruciate ligament (ACL) Augmentation technique Partial rupture Remnant-preserving technique Double bundle KEY POINTS The anterior cruciate ligament (ACL) augmentation technique has potential advantages in terms of proprioceptive function of the knee, revascularization of the graft, and contribution to knee stability. The decision of whether the remaining bundle represents partial rupture or complete rupture of the ACL was made on the basis of physical, magnetic resonance imaging, and arthroscopic findings in a comprehensive manner. Single-bundle ACL reconstruction with remnant-preserving technique is performed in cases of partial rupture of the anteromedial (AM) or posterolateral (PL) bundle of the ACL, and double-bundle ACL reconstruction with remnant-preserving technique is done mainly for patients with continuity of the ACL remnant between the tibia and either the femur or posterior cruciate ligament after complete rupture of the ACL. The femoral and tibial bone tunnel opening should not be placed at the center of the anatomic attachment of the bundle when using hamstring tendons, because the graft shifts to the anterodistal side in the femoral tunnel opening and to the PL side in the tibial tunnel opening. In cases of partial rupture of the AM or PL bundle of the ACL, surgeons should keep in mind that the remaining bundle is not completely intact and it is likely that the biomechanical function of the remaining bundle declines to some extent.
Anterior cruciate ligament (ACL) reconstruction has become a common treatment in orthopedic sports medicine. The normal ACL consists of 2 major functional bundles: the anteromedial (AM) bundle and the posterolateral (PL) bundle. Traditional singlebundle ACL reconstruction has concentrated mainly on the functional restoration of the AM bundle. Recently, several studies have shown that the central anatomic single-bundle ACL reconstruction can restore normal knee function.1–3 With this method, the tibial and Conflict of interest: The authors report no conflict of interest. Department of Orthopaedic Surgery, Integrated Health Sciences, Institute of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan * Corresponding author. E-mail address: [email protected] Clin Sports Med 32 (2013) 127–140 http://dx.doi.org/10.1016/j.csm.2012.08.012 sportsmed.theclinics.com 0278-5919/13/$ – see front matter Ó 2013 Elsevier Inc. All rights reserved.
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femoral tunnels are well placed in the center of their respective ACL footprints. Moreover, interest in double-bundle ACL reconstruction has been growing because of its greater potential to restore knee kinematics.4–8 Double-bundle ACL reconstruction can mimic more closely the normal structure of the ACL. Restoration of the biomechanical function is essential in ACL reconstruction. However, biological healing of the graft is vital to the achievement of satisfying clinical results. Accelerated biological healing is necessary not only for early return to sports but also for reliable remodeling of the grafted tendon. ACL AUGMENTATION Potential Advantages
Arthroscopic examination for ACL reconstruction occasionally demonstrates a relatively thick and abundant ACL remnant. In standard single-bundle or double-bundle ACL reconstruction, the ACL remnant is totally debrided to enable clear visualization of the femoral and tibial bone tunnels. However, recent studies have shown that human ACL remnants contain several types of mechanoreceptors. These mechanoreceptors may provide positive effects on the proprioceptive function of the knee.9–12 In addition, some studies have shown that the ACL remnants provide some biomechanical stability to the knee.13,14 Therefore, ACL reconstruction that preserves the remnant by using the ACL augmentation technique might have several advantages: 1. The ACL remnant may contribute to knee stability and guarantee mechanical strength in the early postoperative period. 2. With respect to the proprioceptive function of the knee, nerve fibers may originate from the preserved ACL remnant and regenerate mechanoreceptors around the augmented graft. 3. The ACL remnant may accelerate cellular proliferation and revascularization of the grafted tendon. Indications
The ACL remnant often maintains a bridge between the tibia and either the intercondylar notch or posterior cruciate ligament (PCL). Even when the substantial remnant maintains a bridge between the tibia and the intercondylar notch, the femoral attachment of the ACL remnant is often positioned abnormally. These cases represent a complete rupture of the ACL. However, sometimes a partial rupture of the AM or PL bundle of the ACL can be observed. In the authors’ previous studies, the frequency of partial rupture was 10% during 2002 and 2005,15 and 20% during 2006 and 2008.13 In these cases, although rupture of the AM bundle or PL bundle could be seen, the other bundle was well preserved, with an attachment of anatomic femoral origin. Partial rupture of the AM or PL bundle of the ACL
Previously, the authors performed the ACL augmentation procedure only for cases of partial rupture of the ACL. In these cases, single-bundle reconstruction of the ruptured bundle is desirable to minimize damage to the femoral attachment of the remaining bundle. Therefore, isolated AM bundle or PL bundle rupture is an indication for the single-bundle augmentation technique. Continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL
In 2008, the authors began performing the ACL augmentation procedure even for patients with continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL. In this complete rupture group, the
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indication for the procedure comprises cases whose ACL remnant maintains a ligamentous bridge between the tibia and either the intercondylar notch or PCL. Initially, central single-bundle ACL reconstruction with the remnant-preserving technique was performed for patients with a complete rupture. Recently, double-bundle reconstruction with the remnant-preserving technique has been performed to mimic more closely the normal structure of the ACL. Preoperative and Intraoperative Evaluation
It is sometimes difficult to decide whether the remaining bundle represents a partial or complete rupture of the ACL. The decision was made after thorough consideration of physical, magnetic resonance imaging (MRI), and arthroscopic findings.13 Quantitative evaluation of anteroposterior knee laxity can be one indicator for this decision. Partial rupture of the ACL was suspected when the side-to-side difference in the anterior displacement of the tibia was less than about 5 mm and a delayed firm end point was noted. The anterior displacement of the tibia was measured by the KT-2000 knee arthrometer or Kneelax-3 at 30 lb (13.6 kg). MRI also provides important information for evaluation of the femoral attachment of the bundles. However, the final decision was made after arthroscopic confirmation of the status of the injured ACL. Evaluation by Arthroscopy
Arthroscopic intra-articular inspection was performed through the standard AM portal, anterolateral portal, and the far AM portal. A thorough arthroscopic probing is needed to precisely assess the ACL remnant patterns. Careful probing on the femoral side is important because most ACL ruptures occur in the proximal half. Partial rupture of the ACL was suspected when ligamentous continuous fibers were observed between the tibia and the anatomic femoral insertion of the ACL. Furthermore, arthroscopic examination should be performed in a figure-of-4 position and at various knee-flexion angles to consider the different tension patterns of the 2 bundles.16–19 Classification of the ACL Remnant
The ACL remnant pattern was thoroughly examined to determine the treatment strategy, and was classified (Box 1). Groups 1a and 1b indicate single-bundle reconstruction with the remnant-preserving technique. Groups 1c, 2a, 2b, and 2c indicate double-bundle reconstruction with the remnant-preserving technique. It is important for surgeons to keep in mind that, even in the partial rupture cases, the remaining bundle is invariably not completely intact. It is likely that the biomechanical function of the remaining bundle declines to some extent. SURGICAL TECHNIQUE
Since 1992, the senior author has performed the ACL augmentation technique when indicated.20 However, the early procedures required 2 incisions at the medial aspect of the proximal tibia and at the lateral femoral condyle, because the grafted tendon was fixed to the femur through the over-the-top route. This early technique had a serious flaw, because it was not a true reconstruction that restored normal ACL anatomy. Therefore, Ochi started to perform the 1-incision technique for ACL augmentation in 1996. Compared with the 2-incision technique, the 1-incision technique is less invasive and enabled reconstruction of the ACL in the anatomic portion. Here the authors introduce the ACL augmentation technique for partial and complete rupture of the ACL.15,21–23
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Box 1 Classification of the ACL remnant Group 1: Partial rupture of the ACL Group 1a: Partial rupture of the PL bundle The ligamentous AM bundle of the ACL had an attachment of femoral origin and was well preserved. Group 1b: Partial rupture of the AM bundle The ligamentous PL bundle of the ACL had an attachment of femoral origin and was well preserved. Group 1c: Partial rupture of the ACL but the remaining bundle could not be ascribed to either the AM or PL bundles Group 2: Complete rupture of the ACL Group 2a: ACL remnant bridging the PCL and tibia The normal attachment of the ACL to the intercondylar notch was entirely lost. Group 2b: ACL remnant bridging the roof of the intercondylar notch and tibia There were no ligamentous continuous fibers in the normal attachment of the ACL to the femur. Diameter of the remnant was somewhat attenuated. Group 2c: ACL remnant bridging lateral wall of the intercondylar notch and tibia Attenuated ACL remnant healed to the lateral wall more arthroscopically anterior than its anatomic origin. There were no ligamentous continuous fibers in the normal attachment of the ACL to the femur. Group 2d: No substantial ACL remnants bridging the tibia and either the femur or the PCL
Patient Positioning and Graft Harvest
The patient was placed supine on the operating table, and a tourniquet was applied around the upper thigh. The knee was placed at 90 of flexion with a foot support and lateral thigh support, and full range of motion was possible. A longitudinal skin incision of approximately 4 cm was made on the anteromedial aspect of the proximal tibia. Semitendinosus and gracilis tendons were identified, and only the semitendinosus tendon was harvested using an open tendon stripper. For the preparation of a tibial bone tunnel, the periosteum was divided longitudinally and reflected medially, just medial to the tibial tubercle. Graft Preparation
In the cases of single-bundle reconstruction with the remnant-preserving technique, a quadrupled semitendinosus tendon was used as the graft for the augmentation. An appropriate size of the EndoButton CL (Acufex; Smith & Nephew, Mansfield, MA) was determined according to the length of the femoral bone tunnel. The quadrupled semitendinosus tendon was connected to the EndoButton CL at the femoral side and to the polyester tapes (EndoButton tape; Acufex; Smith & Nephew) at the tibial side. In the cases of double-bundle augmentation, 2 pieces of doubled semitendinosus tendon were used as a graft. The semitendinosus tendon was divided in half. Each tendon was then doubled, and EndoButton tapes were mechanically connected in series to each free end of the graft. The EndoButton CLs were then connected to each loop end.
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Portal Placement
A 3-portal technique was used. The anterolateral portal was placed as medial (close to the lateral edge of the patellar tendon) as possible to allow visualization of the entire lateral wall of the notch. The AM portal was placed above the joint line, adjacent to the medial edge of the patellar tendon. Finally, the far AM portal was placed as inferior (close to the anterior portion of the medial meniscus) as possible, and 2.5 to 3 cm medial to the medial border of the patellar tendon. The use of this far AM portal for instrumentation allows the AM portal to be used to view the lateral wall of the intercondylar notch. Femoral Bone Tunnel Preparation
There are 2 major techniques for creating a femoral tunnel. One is drilling through the tibial tunnel (transtibial technique) and the other is drilling through the far AM portal (far AM portal technique). The authors regularly use the far AM portal technique, because this technique allows more flexibility in accurate anatomic positioning for femoral tunnel drilling than the transtibial technique. It has been confirmed that the far AM portal technique is as effective as the transtibial technique and results in good restoration of joint stability and knee scores, despite a shorter femoral tunnel length and an inferoposterior position of the EndoButton.24 Excision of the femoral stump using a motorized shaver system was kept to a minimum. No notchplasty was performed. The targeted point for the femoral tunnel was marked with a microfracture awl with the knee at 90 . When performing singlebundle or double-bundle ACL reconstruction using hamstring tendons, the authors hold that the femoral and tibial bone tunnel opening should not be placed at the center of the anatomic attachment of the bundle. The graft is pulled and shifts to the anterodistal side of the femoral tunnel opening and to the PL side of the tibial tunnel opening. When the femoral tunnel is created at the center of the bundle’s femoral footprint, the point of application of force at the tunnel opening shifts from the center of the femoral footprint to an anterodistal direction. The same can be said for the tibial tunnel. Thus, one must recognize that the center of the ACL’s footprint is different from the optimal center of the bone tunnel. The center of the tunnel opening is not the central point of the application of force. It may be true that the biomechanical main part of the femoral attachment of the ACL is on the resident’s ridge, and the remaining part is attached to the posterior portion of the ridge. However, although the femoral tunnel opening can partially include the resident’s ridge, the authors maintain that the center of the femoral tunnel opening should be placed behind the resident’s ridge, for reasons discussed previously (Figs. 1 and 2). Single-bundle reconstruction with the remnant-preserving technique (Groups 1a and 1b)
In cases of PL bundle rupture (group 1a), the aim was to position the central portion of the femoral tunnel between 2 o’clock and 2:30 (left knee) or between 9:30 and 10 o’clock (right knee).23 The marked position indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the AM bundle (see Fig. 1A). Once again, surgeons should keep in mind that the remaining bundle is not intact and that the biomechanical function of the remaining bundle probably declines to some extent. It is unsuitable to create a bone tunnel at the center of the PL bundle attachment. A passing pin was inserted using the far AM portal technique to create a femoral tunnel with 110 to 120 of knee flexion. The length of the tunnel was calculated after increasing the diameter to 4.5 mm with the EndoButton drill. Then a femoral bone socket was created using a headed cannulated reamer of the same diameter as that of the proximal portion of the graft.
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Fig. 1. Femoral bone tunnel placement (short arrow) in single-bundle ACL reconstruction with remnant-preserving technique. (A) In cases of posterolateral (PL) bundle rupture (group 1a), the center of the femoral tunnel was aimed at clock positions between 2:00 and 2:30 (left knee) or between 9:30 and 10:00 (right knee). The marked position (short arrow) indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the anteromedial (AM) bundle. (B) In cases of AM bundle rupture (group 1b), the aim is to position the center of the femoral tunnel between 1:30 and 2:00 (left knee) or between 10:00 and 10:30 (right knee). The marked position (short arrow) indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the PL bundle.
In cases of AM bundle rupture (group 1b), the aim was to position the center of the femoral tunnel between 1:30 and 2 o’clock (left knee) or between 10 o’clock and 10:30 (right knee).23 The marked position indicated that approximately one-quarter of the femoral tunnel opening should include the femoral attachment of the PL bundle (see Fig. 1B). Double-bundle reconstruction with remnant-preserving technique (Groups 1c, 2a, 2b, and 2c)
Through the far AM portal, a passing pin was directed at the targeted point, and the femoral tunnel was subsequently drilled through this portal. Furthermore, the centers of the femoral tunnel openings should be placed posterior to resident’s ridge (see Fig. 2).22 In group 2b, both the targeted points for the AM and PL femoral tunnels are posterior to the femoral attachment of the ACL remnant. In groups 1c and 2c, although the targeted point for the PL femoral tunnel is distal and posterior to the femoral attachment of the ACL remnant, the targeted point for the AM femoral tunnel is proximal and anterior to the ACL remnant, because the positions of the ACL remnants in groups 1c and 2c are more posterior than those in groups 2a and 2b. Therefore, in groups 1c and 2c, the ACL remnant is sandwiched between the 2 grafted tendons. The passing pin was drilled through the femur to emerge on the lateral aspect of the thigh. After the passing pin was drilled, the procedure was the same as for singlebundle augmentation (see Fig. 2C). Tibial Bone Tunnel Preparation
Tibial attachment of the ACL remnant is a useful landmark for orientation because in most cases the tibial side of the ACL remnant is almost normal. A longitudinal slit was made at the center of the ACL remnant through the AM portal (Fig. 3A). The tip of the tibial drill guide (Director Drill Guide System; Acufex; Smith & Nephew) was inserted
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Fig. 2. Femoral bone tunnel preparation in group 2b (ACL remnant [black arrow] bridging the roof of the intercondylar notch and tibia; right knee). (A) The targeted point for the PL femoral tunnel was marked with a microfracture awl with the knee at 90 . (B) The point for the AM femoral tunnel. (C) Femoral bone tunnels for double-bundle augmentation. (D) Schematic (left knee) of femoral tunnel placement for AM and PL bundle.
through the AM portal. The tip was then put through the slit of the ACL remnant at an angle of up to 65 to the tibial plateau to allow visualization of the tip of the Kirschner wire (Fig. 3B).22 Single-bundle reconstruction with remnant-preserving technique (Groups 1a and 1b)
In cases of PL bundle rupture (group 1a), the tip of the drill guide was positioned in the center of the tibial insertion of the whole ACL. Then a 2.0-mm Kirschner wire was inserted using the drill guide. When the position of the Kirschner wire was satisfactory, the wire was carefully advanced by a conventional cannulated reamer to create a tibial bone tunnel. The size of the reamer was 0.5 mm smaller than the diameter of the distal portion of the graft. The tibial tunnel was then enlarged to the graft diameter with the appropriate tunnel dilator. In cases of AM bundle rupture (group 1b), the tibial tunnel opening should be positioned as anterior as possible within the tibial footprint of the ACL.23 The position of the guide wire was then checked with the knee extended, to see if the guide wire impinged on the roof of the intercondylar notch. Double-bundle reconstruction with remnant-preserving technique (Groups 1c, 2a, 2b, and 2c)
The tip of the tibial drill guide was put through the slit of the ACL remnant. Two 2.0-mm Kirschner wires were inserted into the tibial attachment of the ACL remnant using the
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Fig. 3. Tibial bone tunnel preparation in group 2c (ACL remnant [long black arrow] bridging lateral wall of the intercondylar notch and tibia; right knee). (A) A longitudinal slit was made at the center of the ACL remnant. (B) The tip of the tibial drill guide was put through the slit of the ACL remnant. (C) The Kirschner wire for the PL bundle (short black arrow) was inserted at 8 mm posterior to the wire for the AM bundle (short white arrow).
drill guide. The drill guide was set at an angle of up to 65 to the tibial plateau, to allow visualization of the tip of the wires. The Kirschner wire for the AM bundle should be inserted to enable the tibial tunnel opening of the AM bundle to be positioned as anterior as possible within the tibial footprint of the ACL.22 The Kirschner wire for the PL bundle was inserted at 8 mm posterior to the wire for the AM bundle to keep 2 to 3 mm thick of bony wall between the tibial bone tunnels (Fig. 3C). Therefore, it is necessary to make a longitudinal slit in the ACL remnant to visualize the tips of the guide wires. In addition, when using the transtibial technique, it is difficult to find the tip of the Kirschner wire for the PL bundle in the slit, because this technique requires the wire to be inserted at a shallower angle to the tibial plateau. As a result, the wire for the PL bundle will be parallel to the preserved ACL remnant. Therefore, the use of an image intensifier is required for intraoperative localization of the wire when using the transtibial technique. However, the use of an image intensifier has several risks including radiation exposure, extended time in surgery, infection, and lower accuracy of measuring the distance between the wires than arthroscopy. The authors recommend the far AM portal technique, because it does not impose any restrictions on the angle of the tibial tunnel. Increasing the inclination of the tibial tunnels to 65 allows for better visualization of the tips of the guide wires. After the passing pin was drilled, the procedure was the same as for single-bundle augmentation.
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Graft Passage and Fixation
Graft passage depends on the patterns of the ACL remnant and can be either through or above the slit of the ACL remnant.22 Graft passing through the slit of the ACL remnant
For cases such as partial rupture of the PL bundle, if the graft passes above the ACL remnant, the positional relationship is anatomically incorrect and there is a danger of impingement, whereby the graft should pass through the slit of the ACL remnant. To prepare for this method, a curved hemostat was passed through the slit to create a passage to the intra-articular aperture of the femoral tunnel. All of the grafts for the PL bundle as well as grafts for the AM bundle in groups 2a and 2b are indications of this method. Fig. 4 shows an example of a graft passage for the PL bundle in group 2c. The creation of a passage through the ACL remnant allows minimal impingement of the ACL remnant against the reconstruction graft and the roof of the intercondylar notch. Graft passing above the ACL remnant
As for the grafts for the AM bundle in groups 1b, 1c, and 2c, a looped Ethibond suture passed above the ACL remnant (Fig. 5). The graft composites were introduced from the tibial tunnel to the femoral tunnel using the looped Ethibond suture (Fig. 6). The
Fig. 4. Preparation of graft passage for the PL bundle in group 2c (right knee). (A) A curved hemostat was passed through the slit (arrow) to create a passage to the intra-articular aperture of the femoral tunnel. (B, C) A looped Ethibond suture for later introduction of the graft for the PL bundle was retrieved by the curved hemostat through the longitudinal slit in the ACL remnant. (D) An arthroscopic grasper was subsequently used to pass the retrieved Ethibond suture for the PL bundle into the created tibial tunnel for the PL bundle.
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Fig. 5. Preparation of graft passage for the AM bundle in group 2c (right knee). A looped Ethibond suture for later introduction of the graft for the AM bundle was passed above the ACL remnant and was retrieved into the created tibial tunnel for the AM bundle by an arthroscopic grasper.
Fig. 6. Graft passage of the PL and AM bundles in group 2c (right knee). (A) Both looped Ethibond sutures for introduction of the PL bundle graft (white arrow) and AM bundle grafts (black arrow) passed under and above the ACL remnant, respectively. (B) First, the graft for the PL bundle (arrow) was introduced from the tibial tunnel to the femoral tunnel. (C) Second, the graft for the AM bundle (arrow) was introduced into the joint. In groups 2c and 1c, the ACL remnant was sandwiched between the 2 grafted tendons.
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proximal side of the graft was fixed to the lateral femoral cortex by flipping the Endobutton and pulling the graft distally. Change in the length of the graft was examined during knee flexion-extension motion. In single-bundle augmentation, a tension force of 50 N was applied to the distal Endobutton tape connected to the graft and this was secured with 2 staples (Meira, Nagoya, Japan) at 30 of knee flexion. In double-bundle augmentation, a tension force of 30 N was applied to the EndoButton tape of each graft. The EndoButton tapes were fixed with 2 staples each at a knee flexion angle of 15 for the PL bundle and 40 for the AM bundle. Finally, the separated ACL remnant at the slit was sutured onto the graft to create a closed tube (Fig. 7). The authors first performed the ACL augmentation technique in 2011, using a quadriceps tendon– patellar bone autograft. Bone–patellar tendon–bone and quadriceps tendon can be good options for the augmentation technique (Fig. 8). CLINICAL RESULTS IN THE LITERATURE
In 2000, Adachi and colleagues20 reported that the joint stability and proprioceptive function in 40 patients who underwent the ACL augmentation procedure were superior to those of 40 patients who underwent standard ACL reconstruction during the same period. However, as mentioned, the early procedures needed 2 incisions and were not true reconstructions that restored normal ACL anatomy. Therefore, Ochi and colleagues15 started to perform the ACL augmentation 1-incision technique for the partial rupture of the AM or PL bundle of the ACL, publishing their first report in 2006. Later, Ochi and colleagues21 also showed that ACL augmentation using the 1-incision technique substantially improved joint stability, the joint position sense, and the Lysholm score postoperatively in cases of partial ACL rupture. Recently, other orthopedic surgeons also demonstrated favorable clinical results using the ACL augmentation technique.16,25–29 The preliminary results from Siebold and Fu16 using autologous doubled or tripled semitendinosus tendon showed good clinical outcomes for AM and PL bundle augmentation at an average of 1 year postoperatively. Ahn and colleagues28 reported good clinical and MRI results for
Fig. 7. Final arthroscopic view of double-bundle reconstruction with remnant-preserving technique in group 2b (right knee). In this group, both grafts for the AM bundle (hidden) and PL bundle (arrow) passed under the ACL remnant. The separated ACL remnant at the slit was sutured onto the graft.
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Fig. 8. ACL augmentation technique using quadriceps tendon–patellar bone autograft. (A) Quadriceps tendon–patellar bone autograft (black arrow, quadriceps tendon; white arrow, patellar bone). (B) Three-dimensional computed tomography image of the femoral side (arrow, bone block in the femoral tunnel). (C) Coronal computed tomography image of the femoral side (arrow, bone block in the femoral tunnel).
single-bundle ACL reconstruction using the remnant preservation and femoral tensioning technique. Longer follow-up is necessary before a definitive conclusion can be reached, especially regarding the double-bundle augmentation technique. Nevertheless, the authors believe that this technique of preserving the remnant tissue of the ACL is a valuable procedure, especially in terms of biological healing of the grafted tendon. In the near future, a navigation system may play an important role in the ACL augmentation procedure. SUMMARY
In ACL reconstruction, biological healing of the graft is vital to the achievement of satisfactory clinical results. The ACL augmentation technique has potential advantages in terms of proprioceptive function of the knee, revascularization of the graft, and contribution to knee stability. The decision of whether the remaining bundle represents partial or complete rupture of the ACL has to be made on the basis of thorough and comprehensive physical examination, MRI, and arthroscopic findings. Singlebundle reconstruction with the remnant-preserving technique is performed in cases of partial rupture of either AM or PL bundle, and double-bundle reconstruction with the remnant-preserving technique is performed mainly for patients with continuity of the ACL remnant between the tibia and either the femur or PCL after complete rupture of the ACL. However, in cases of partial rupture of the AM or PL bundle, surgeons should keep in mind that the remaining bundle is not completely intact and that the
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biomechanical function of the remaining bundle probably declines to some extent. Although longer follow-up is necessary before a definitive conclusion can be reached, the authors believe that this technique is a valuable procedure. REFERENCES
1. Ho JY, Gardiner A, Shah V, et al. Equal kinematics between central anatomic single-bundle and double-bundle anterior cruciate ligament reconstructions. Arthroscopy 2009;25:464–72. 2. Asagumo H, Kimura M, Kobayashi Y, et al. Anatomic reconstruction of the anterior cruciate ligament using double-bundle hamstring tendons: surgical techniques, clinical outcomes, and complications. Arthroscopy 2007;23:602–9. 3. Kanaya A, Ochi M, Deie M, et al. Intraoperative evaluation of anteroposterior and rotational stabilities in anterior cruciate ligament reconstruction: lower femoral tunnel placed single-bundle versus double-bundle reconstruction. Knee Surg Sports Traumatol Arthrosc 2009;17:907–13. 4. Kondo E, Merican AM, Yasuda K, et al. Biomechanical comparisons of knee stability after anterior cruciate ligament reconstruction between 2 clinically available transtibial procedures: anatomic double bundle versus single bundle. Am J Sports Med 2010;38:1349–58. 5. Petersen W, Tretow H, Weimann A, et al. Biomechanical evaluation of 2 techniques for double-bundle anterior cruciate ligament reconstruction. Am J Sports Med 2007;35:228–34. 6. Hussein M, van Eck CF, Cretnik A, et al. Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up. Am J Sports Med 2011;40:512–20. 7. Buoncristiani AM, Tjoumakaris FP, Starman JS, et al. Anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy 2006;22:1000–6. 8. Fu FH, Shen W, Starman JS, et al. Primary anatomic double-bundle anterior cruciate ligament reconstruction: a preliminary 2-year prospective study. Am J Sports Med 2008;36:1263–74. 9. Adachi N, Ochi M, Uchino Y, et al. Contribution of mechanoreceptors in the anterior cruciate ligament to the joint position sense knee. Acta Orthop Scand 2002;73:330–4. 10. Denti M, Monteleone M, Berardi A, et al. Anterior cruciate ligament mechanoreceptors. Histologic studies on lesions and reconstruction. Clin Orthop Relat Res 1994;308:29–32. 11. Ochi M, Iwasa J, Uchino Y, et al. The regeneration of sensory neurones in the reconstruction of the anterior cruciate ligament. J Bone Joint Surg Br 1999;81:902–6. 12. Ochi M, Iwasa J, Uchino Y, et al. Induction of somatosensory evoked potentials by mechanical stimulation in reconstructed human anterior cruciate ligaments. J Bone Joint Surg Br 2002;84:761–6. 13. Nakamae A, Ochi M, Deie M, et al. Biomechanical function of anterior cruciate ligament remnants: how long do they contribute to knee stability after injury in patients with complete tears? Arthroscopy 2010;26:1577–85. 14. Crain EH, Fithian DC, Paxton EW, et al. Variation in anterior cruciate ligament scar pattern: does the scar pattern affect anterior laxity in anterior cruciate ligamentdeficient knees? Arthroscopy 2005;21:19–24. 15. Ochi M, Adachi N, Deie M, et al. Anterior cruciate ligament augmentation procedure with a 1-incision technique: anteromedial bundle or posterolateral bundle reconstruction. Arthroscopy 2006;22:463.e1–5.
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16. Siebold R, Fu FH. Assessment and augmentation of symptomatic anteromedial or posterolateral bundle tears of the anterior cruciate ligament. Arthroscopy 2008; 24:1289–98. 17. Petersen W, Zantop T. Partial rupture of the anterior cruciate ligament. Arthroscopy 2006;22:1143–5. 18. Sonnery-Cottet B, Chambat P. Arthroscopic identification of the anterior cruciate ligament posterolateral bundle: the figure-of-four position. Arthroscopy 2007;23: 1128.e1–3. 19. Sonnery-Cottet B, Barth J, Graveleau N, et al. Arthroscopic identification of isolated tear of the posterolateral bundle of the anterior cruciate ligament. Arthroscopy 2009;25:728–32. 20. Adachi N, Ochi M, Uchio Y, et al. Anterior cruciate ligament augmentation under arthroscopy. A minimum 2-year follow-up in 40 patients. Arch Orthop Trauma Surg 2000;120:128–33. 21. Ochi M, Adachi N, Uchio Y, et al. A minimum 2-year follow-up after selective anteromedial or posterolateral bundle anterior cruciate ligament reconstruction. Arthroscopy 2009;25:117–22. 22. Ochi M, Abouheif MM, Kongcharoensombat W, et al. Double bundle arthroscopic anterior cruciate ligament reconstruction with remnant preserving technique using a hamstring autograft. Sports Med Arthrosc Rehabil Ther Technol 2011;3:30. 23. Nakamae A, Deie M, Adachi N, et al. Augmentation procedure for partial rupture of the anterior cruciate ligament. Tech Knee Surg 2010;9:194–200. 24. Nakamae A, Ochi M, Adachi N, et al. Clinical comparisons between the transtibial technique and the far anteromedial portal technique for posterolateral femoral tunnel drilling in anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy 2012;28:658–66. 25. Kim SJ, Jo SB, Kim TW, et al. A modified arthroscopic anterior cruciate ligament double-bundle reconstruction technique with autogenous quadriceps tendon graft: remnant-preserving technique. Arch Orthop Trauma Surg 2009;129:403–7. 26. Yoon KH, Bae DK, Cho SM, et al. Standard anterior cruciate ligament reconstruction versus isolated single-bundle augmentation with hamstring autograft. Arthroscopy 2009;25:1265–74. 27. Sonnery-Cottet B, Lavoie F, Ogassawara R, et al. Selective anteromedial bundle reconstruction in partial ACL tears: a series of 36 patients with mean 24 months follow-up. Knee Surg Sports Traumatol Arthrosc 2010;18:47–51. 28. Ahn JH, Wang JH, Lee YS, et al. Anterior cruciate ligament reconstruction using remnant preservation and a femoral tensioning technique: clinical and magnetic resonance imaging results. Arthroscopy 2011;27:1079–89. 29. Lee BI, Kwon SW, Kim JB, et al. Comparison of clinical results according to amount of preserved remnant in arthroscopic anterior cruciate ligament reconstruction using quadrupled hamstring graft. Arthroscopy 2008;24:560–8.